If they were scanned and added to the library, we could solve the problem that an MP3 file can only have one album, but I have many Mp3 files belonging to different albums.

I imagine the structure of a folder as follows

MySongs
-> mp3/Artist1/Trackname.mp3
-> mp3/Artist2/Trackname.mp3
-> mp3/Artist3/Trackname.mp3

-> sxpf/Album1/Artist1/Trackname.sxpf
-> sxpf/Album1/Artist3/Trackname.sxpf

-> sxpf/Album2/Artist3 - trackname.sxpf
-> sxpf/Album2/Artist2 - trackname.sxpf

The sxpf file can contain track number of the track in the album, and so on, and we don't have to save the same mp3 file X times just because of the tags.

The Media Lib could treat the SXPF files like MP3 files by reading the tags from the SXPF file and using the real mp3 files as real binary data